Trier Social Stress Test for Assessing Psychosocial Stress Based on Heart Rate Variability Parameters in Male and Female Students of a Higher Educational Institution

BACKGROUND: The study of heart rate variability under short-term experimentally induced psychosocial stress is important for understanding the mechanisms of autonomic regulation of cardiac activity. AIM: The work aimed to investigate the changes of heart rate variability parameters during short-term intensive exposure to psychosocial stress factors using the Trier Social Stress Test in male and female first- and second-year students of a higher educational institution. METHODS: It was a prospective study. Inclusion criteria: health group I or II; age 19–22 years; willingness to participate and strong motivation for high performance. Exclusion criteria: any degree of obesity; history of chronic cardiovascular or neurological diseases. Two groups were formed according to sex: group 1, females; group 2, males. Acute psychosocial stress was induced using a modified Trier Social Stress Test protocol. At each stage, a 5-minute segment of cardiointerval recording was obtained for subsequent heart rate variability analysis. RESULTS: The study included 79 volunteers enrolled in the 1st–2nd years of full-time university education. Females and males were assigned to group 1 (n = 41) and group 2 (n = 38), respectively. From the first (control) phase of the Trier Social Stress Test, differences in heart rate variability parameters were observed between groups despite low subjective stress reports. In the second phase, both groups demonstrated increased heart rate and low-frequency spectral power, along with decreased normalized RR interval duration and high-frequency spectral power. Reactivity phase showed the highest subjective stress ratings and maximal heart rate variability alterations compared with the control stage. An increase in heart rate (especially in group 1 during self-presentation), centralization index, vagosympathetic interaction index, low- and very-low-frequency spectral power, the difference between maximum and minimum RR intervals, as well as the standard deviation of the full set of RR intervals (predominantly in group 2) was noted. In addition, a decrease in the mean duration of the normalized RR interval and in the high-frequency spectral power was observed. By the fifth phase, with moderate subjective stress persisting, sympatho-parasympathetic balance was largely restored in both groups, with some sympathetic predominance in integral heart rate variability measures. CONCLUSION: Thus, males showed a trophotropic pattern of changes in the activity of regulatory systems, characterized by moderate inhibition of vagal influences along with sympathoadrenal activation during acute psychosocial stress. In females, stress-induced heart rate variability alterations were more pronounced and ergotropic in nature.